Electronic switching arrangement for time keeping equipment

ABSTRACT

A self-exciting electronic circuit for driving the mechanical rate element of a time-keeping device including means to vary the width of the drive pulse to compensate for amplitude differences caused by temperature or voltage changes.

United States Patent [721 Inventor Robert W. Reich Vln Noledl 8,(Iii-6977 Ruvigliana, Switzerland [21 1 Appl. No 800,146 [22] Filed Feb.I8, 1969 [4S] Patented July 13, 197i (32} Priority Oct. 20, I968 [33]Switzerland [3! 15737/68 [54] ELECTRONIC SWITCHING ARRANGEMENT FOR TIMEKEEPING EQUIPMENT 3 ClaimsJ Drawing Fig.

[52] U.S.Cl .r 33l/li6,

58/23,33l/109,33lll56 [5! Int. Cl. "03b 5/36 [50] FleidolSelrch.33l/l09, H6, 156; 58/23 I 5 6] References Cited UNITED STATES PATENTS2.895.095 7/1959 Guyton H 331/1 l6 3.336.537 8/l967 Reich 331/] I6Primary Examiner-John Kominski Arramey- Arthur Schwartz ABSTRACT: Aself-exciting electronic circuit for driving the mechanical rate elementof a timekeeping device including means to vary the width of the drivepulse to compensate for amplitude differences caused by temperature orvoltage changes.

vmnmm JUL 1 3 :91: 3.593; 200

INVENTOR R0 5: n1 WALT in Rn n A RTHuR ScuwAn-ri Afl'oRNE Y ELECTRONICSWITCHING ARRANGEMENT FOR TIME KEEPING EQUIPMENT BACKGROUND OF THEINVENTION l. Field of the Invention This invention relates to anelectronic switching circuit for clocks and other timekeeping equipmentwith any desired magnet system.

2. Description of the Prior Art In the electronic circuits currentlyused with time keeping equipment, the accuracy of the clock speeddepends on the voltage and temperature affecting the circuits and thisdepen dance in turn can be traced back mainly to the transistorproperties. Attempts have been made to eliminate the temperaturedependence primarily by using various switching techniquesv To eliminatethe voltage dependence. breakdown diodes have been preferred These knownmeasures do produce a more or less significant success which isobtained. however, at the expense ofa considerable output loss because.based on the level of the minimum output available immediately prior tobattery replacement. the initial surplus portion of the output isintentionally lost. Such an output loss is particularly disadvantageousin a small clock which works with a supply voltage of only about 1 volt.

SUMMARY OF THE INVENTION This invention provides a completely newelectronic circuit for clocks and other timekeeping equipment, for usewith any desired magnet system. Both the way of looking at the problemand the means of solution ofthe problem are new.

The novel circuit is characterized by the fact that it is selfexcitingand that it is adapted to elongate the pulse width upon decrease ofvoltage or temperature (and their effective combination, respectively,)and to shorten the pulse width upon increase of voltage or temperature(and their effective combination, respectively,) thereby keepingconstant the product of voltage and time t. i.e. the pulse intensity: Vr=!.

The basic technical improvement over all known circuits with voltage andtemperature compensation is that the new circuit works without loss.Furthermore, the operating range can be expanded in a very simple mannerto include supply voltages of up to about 24 volts.

BRIEF DESCRIPTION OF THE DRAWING The electronic circuit according to theinvention is illustrated in the sole figure by way of example.

DESCRIPTION OF THE PREFERRED EMBODIMENT The circuit shown comprises twocoils L,, L,, which cooperate in a known manner with any desired magnetsystem (not illustrated). It is immaterial here whether the magnetsystem is fixed to the rate regulator and the coils are stationary orvice versa. It is only important that the relative motion between themagnet system and the coils causes the coils periodically to get intothe magnetic field and thus to be cou pled. Furthermore, there are twotransistors T, and T, of the same type (in the drawing, they areillustrated as NPN type but the PNP type could be used in acorresponding altered circuit). The first transistor T, is connectedwith the second transistor T, while the first coil L, is connected inbetween the two. Between the emitter and the negative terminal of thevoltage source (not further illustrated) is the second coil L Thecollectors of transistors T, and T, are connected to the positiveterminal of the battery, as is the base of the first transistor T,. thelatter being connected via a resistance R. A capacitive feedback link C,is arranged between the emitter of the second transistor T and the baseof the first transistor T, A capacitor C is connected between the baseand the collector of the first transistor T, for the attenuation ofspurious parasitic oscillations. Resistance R which is connected betweenthe base and the emitter of the first transistor T,, and is used toadjust the pulse ratio. Ii necessary here only if the battery voltage isgreater than about !.6 volts (up to a maxmum of about 24 volts]. Thenresistance R, IS in the range of several kilohms. while a high-impedanceresistance is provided as R The capacitive feedback link C, and coil L,which thus are connected in series are bridged by three silicon diodes D(two diodes are enough at a battery voltage of up to 1.5 volts) By thesilicon diodes D the voltage on the emitter of the transistor T, islimited and thereby the maximum pulse amplitude. The capacitor C,couples the pulse from the emitter of the transistor T, to the base ofthe transistor T,. Though the voltage on the emitter of the transistorT, is constant by variations of the battery voltage the voltage on theemitter of the transistor T varies, If the battery is fresh full voltageis on the emitter of the transistor T and the capacitor C, is dischargedduring a predetermined period of time. If the battery voltage and inconsequence the voltage on the emitter of the transistor T, drops offthe time for discharging of the capacitor C, is rising and bothtransistors are conductive during a longer period of time than with thefull voltage.

The circuit illustrated operates in such a fashion that, due to thesudden self-excitation start, the first transistor T, becomes conductiveand thus causes the second transistor T to become conductive. Thepositive voltage occurring at the emitter of the second transistor T isapplied to the base of the first transistor T, by means of feedback linkC because of which this first transistor becomes even more stronglyconductive. Thus the current. flowing through coils L, and L isamplified in avalanche-fashion. Both coils operate as working coils. Thecircuit thus. in contrast to all previously known circuits, does notreveal a special exciter coil. The processes in the switchingarrangement are triggered the moment both coils are connected by themagnetic field of the magnet system. while there is a disconnectionduring the departure from the magnetic field and the processes in theswitching arrangement are thus cut off.

Since transistors T, and T are not connected in a complementary fashion,this is not dealing here with a multivibrator but rather with acompletely new circuit in which one can determine the energy level byselecting R and C,v When C, is smaller there is a larger amplitude andwhen R is larger there is a smaller amplitude, As the temperature drops,there is a greater impulse width.

In a typical circuit according to the present invention, after one daythe temperature and voltage errors are smaller than one second perdegree Centigrade or per volt so that the spring error is alsocontrolled here.

I claim:

1. A self-exciting electronic circuit for timekeeping equipment adaptedfor magnetic interaction with a magnet means to thereby physically drivesaid equipment, comprising:

a. positive and negative terminals adapted to supply DC power,

b. a first and second coils adapted to be coupled by said magnet means,

c. a first and second transistor of the same conductivity type, saidfirst transistor being intercoupled in cascade through said first coilwith said second transistor connected through said second coil to one ofsaid terminals,

d. a feedback link consisting of a first capacitor connected between theoutput of said second transistor and the base of said first transistor,

e. a first resistor connected between the base of said first transistorand the other of said terminals,

f. means for connecting the input of said first transistor to the otherof said terminals,

g. means for connecting the input of said second transistor to the otherof said terminals, and

h. a second capacitor connected between the input and the base of saidfirst transistor.

2. A circuit according to claim 1. wherein a point between the firstcoil and the first transistor is connected through a second resistor tothe base of the first transistor.

3, A circuit according to claim 2, wherein the feedback link and thethus series connected second coil are bridged by at least two silicondiodes.

1. A self-exciting electronic circuit for timekeeping equipment adaptedfor magnetic interaction with a magnet means to thereby physically drivesaid equipment, comprising: a. positive and negative terminals adaptedto supply DC power, b. a first and second coils adapted to be coupled bysaid magnet means, c. a first and second transistor of the sameconductivity type, said first Transistor being intercoupled in cascadethrough said first coil with said second transistor connected throughsaid second coil to one of said terminals, d. a feedback link consistingof a first capacitor connected between the output of said secondtransistor and the base of said first transistor, e. a first resistorconnected between the base of said first transistor and the other ofsaid terminals, f. means for connecting the input of said firsttransistor to the other of said terminals, g. means for connecting theinput of said second transistor to the other of said terminals, and h. asecond capacitor connected between the input and the base of said firsttransistor.
 2. A circuit according to claim 1, wherein a point betweenthe first coil and the first transistor is connected through a secondresistor to the base of the first transistor.
 3. A circuit according toclaim 2, wherein the feedback link and the thus series connected secondcoil are bridged by at least two silicon diodes.